My chicken and egg guy is in the little market between Charcas and Guemes on Jeronimo Salguero.
There are about a dozen small stalls there.
His eggs are cheaper than the disco, and much better tasting, with real yellow yolks.
And his chickens come direct from a granja.
Its funny- I know a couple of Argentines who are so busy- usually two or more jobs, kids, and no time- who order out, and eat storebought milanesas, empanadas, and pizza- but the four or five Argentine friends I have who I eat at their houses the most often are all incredible gourmet cooks, who are quite versed in vegetables and world cuisine.
But then, I live (in Buenos Aires) in the middle of things, not way out in the burbs, and I find the people more worldly and interested in life. Also, its easy for me to go to a half dozen different markets (not supermarkets, but farmers markets and old style gallerias of many different vendors) I often go to the Armenian stores on Scalabrini Ortiz, and I go to El Galpon, in Chacarita, every week or two, for organic and homemade cheeses, meats, and fresh from the farmer produce.
I buy honey and home made jams and liqueurs from a woman who is in the San Telmo markets on weekends- she makes all her own products, including orange and citrus marmalades my wife swears by.
Lots of small specialty stores near me sell much higher quality stuff than Disco or Jumbo, too.
Some of absolutely costs more, but you can taste the difference.
The good stuff is out there, you just have to look for it.
http://pickupthefork.com/shopping-guide/